Centrifugal pump.



J. SGHNBIBLE.

GENTRIFUGAL PUMP.

APPLICATION FILED JUNE 18, 1912. 1,065,732. Patented June 24,1913.

Z SHEETS-SHEET 1.

J. SCHNEIBLE.

GENTRIFUGAL PUMP.

APPLICATION FILED JUNE 1s, 1912.

1,065,732, l y Patented June 24,1913` 2 SHEETS-*SHEET 2` UNITED STATESPATENT OFFICE.

JOSEPH SCHNEIBLE, OF CHICAGO, ILLINOIS.

CENTRIFUGAL PUMP.

To all coll-0mi 15 may concern Be it known that I, JOSEPH SCHNEIBLE, acitizen of the United States, residing at 122 South Michigan avenue,Chicago, in the county of Cook and State of Illinois, have invented anew and useful Improvement in Centrifugal Pumps, of which the followingis a specification.

My invention relates to an improvement in the class of centrifugal pumpsemploying closed or shrouded impellers for prevent-ing leakage throughthe clearance-space betweei'i 'the impeller and side-walls o-f thepumpcasing from the outer circumference of the impeller inwardly towardthe intake or suction-pipe of the pump.

The closed impeller, as hitherto constructcd, is not adequatelyeffective for the aforesaid anti-leakage purpose excepting in pumps oflarge capacity. 'Ihe attempt heretofore made, in centrifugal pumps ofsmaller capacity, to accomplish the aforesaid purpose of reducing to theminimum the quantity of such leakage, has been by providing between theimpeller-shrouding and sides of the pump-casing a very closeclearancespace leading to the suction-pipe connection and requiring t-hefluid, after passing through that space, to iow through a labyrinth ofrims or rings 4provided to reduce it. I-Iowever, even with thatconstruction the clearance-space loss is so great, that in determining'the dimensions of the impeller for any given pump, the quantity of suchloss has to be taken into account, because that quantity passes throughthe impeller in addition to the fluid being discharged by the pump.Moreover, that construction renders multi-staging necessary, even thoughthe pressure sought might readily be attained by the action of a singleimpeller, were it not for the fact that the greater' the differencebetween the pressure at the impeller-rim and the suction-pressure thegreater will be the quantity of leakage.

The object of my invent-ion is to provide a simple construction ofimpeller-shrouding which shall effectively overcome the difficulty inpreventing the leakage referred to; and this I accomplish by providingthe sidewalls on the impeller-blades, forming the impeller-shroud, withspiral passages about their outer faces, with the effect hereinafterexplained.

In the accompanying drawings, Figure 1 Specification of Letters Patent.Patgnted June 24, 1913 Application led June 18, 1912.

Serial No. 704,381.

shows a centrifugal pump embodying my improvement by a section on line 1F ig. 2, with t-he impeller in elevation, and F ig. 2 is a diametricalsect-ion through the pump on line 2, Fig. l.

The pump-casing 3, which may be of the construction illust-rated or ofany other desired construct-ion, need involve no features of novelty. Ithas the intake Ll at the apex of the conical section 5 of one of itsheads, and the peripheral outlet 6, as usual in such pumps; and betweenthe annular outlet chamber 7 and impeller the inner surfaces of thecasing-heads are formed with corresponding annular shoulders 71. Theimpeller 8, formed with a series of curved blades 9, is secured at itshub 10 to the drive-shaft 11 journaled in a head of the casing pro-videdwith a stufling-box 12 and a. standard or leg 13 to be bolted to asuitable bed for stably supporting the pump in its operative position.

On opposite sides of the impeller-blades are pro-vided, or cast integraltherewith, annular walls 14, 14, to form the impellershroud; and theyextend inwardly from the blade-tip extremities a comparatively-shortdistance toward the hub, or to any distance most suitable for theirpurpose. Similar spiral channels or passages 15, 15 extend about thewalls 14 on their outer surfaces, describing courses running from theinner edges of the walls outwardly and in the direction opposite to thedirection of rotation of the impeller, to form fluid-ways between thesmooth sides of the casing-heads.

Relatively short vanes 16 are shown by dotted lines in Fig. 1 to beprovided between the impeller-blades on the inner faces of the walls 14,but they are not novel and are not necessary for use with myimprovement.

In operating the pump, the impeller, which revolves freely in thecasing, in producing outward motion of the fluid, generates by theaction of the entire cross-section of both outer surfaces of theshrouding suflicient force thereon between the pump-casing andimpeller-shroud to counteract and thus prevent back-flow, (due todifference in pressure within the clearancespace between the shrouding`and pump-casing) of the fluid through the clearance-space 16 from theperiphery of the impeller toward the center of the pump, while at thesame time maintaining a counter-pressure throughout the clearance-spacecorresponding to the pressure set up b y the impeller-action.

As will be understood, in the operation ot a centritugal pump aconstai'it increase ot pressure is produced on the tluid as it movesradially troni the z Xis toward the iinpellerrim, where the pressurereaches its highest point. This is due to the constantly increasingrotating` velocity of the outwardly, and, con'iparatively, slowly movingtluid; and in consetpience of this di'l'lerence in pressure, the iluidtends to How through the clearance-space lauzkwardly toward thesuctionpipe, causing the loss referred to, which inipaii's theetlicii-incy ot the pump and constii tutes the so-called clearance-spaceloss. This my iiiiprcveinent prevents, as aforesaid, because it` rendersunnecessary close clearance between the rotating impeller and thesuction-pipe; and since the outwaiL'dly-impelling force set up 'in theclearance-space at both sides of the impeller necessarily takes placenear the impeller-riin, the walls 'ist need not. extend inwardly fartherthan is required to properly shroud the blade-tips, and a whollyunoliistructed entrance to the iinpeller is aliorded, which leaves theiimei' portion of the pun'iijiing chamber tree from any inipeller-casingand thereby almost totally avoids axial thrust, because et' the equalpressure within the part of the pumpcasing in which the impellerrotates.

lt should be emphasized that the shrouded impeller, in the present case,is not, in etl'ect, a siippleinentary pumping medium operating to torcethe fluid in the clearancespace into the discharging tluid byovercomingl the back-pressure resistance ot' the latter; but that itoperates to create and maintain in the clearance-space a iliracticallyconstantI pressure, as an equilibrium to the back-pressure otthedischarging Huid, presentingI a stat-ical pressure-torce between theclearance-space and discharge of the pump to shut ott theclearance-space against being overcome bv back-pressure from thedischarge. In the particular means l have provided for my purpose, thepitch-angle ot' the spiral-shaped vanes is sutliciently tlat. to set. upthis statical pressure lwithin the clearance-space without causingradial outward flow therein. That pitch, ot course, as will beunderstood, rshould be changed to adapt it to the physical condition otthe fluid to be pumped, meaning that 'for viscous liquids thepitch-angle should be flatter than for mobile liquids.

I realize that considerable variation is possible in the details ofconstruction thus specifically shown and described, and i do not intendby illustrating a single, specilic or preferred torni to limit myinvention thereto, my intention being in the following claims to claimprotection upon all the novelty there may be in my improvement asbroadly as the state of the art will permit. Thus, while the spiraltorni of the counterpressure-producing means herein described isbelieved to best, serve my purpose, the purpose being to provide suchcouiiter-pressure, any other means on the outer 'faces of the annularshroud-walls that will etfectthe same result are within my invention.

1What l claim as ne i and desire to secure by Letters Patent, is

' l. ln a centi'itugal pump, an impeller adapted to prevent back-leakageof tluid through the clearance-space in the pump, comprising annularshroud-forming walls on opposite sides of the iiupeller-blades, providedon their outei' 'faces with means producing and maintaining, by therotation of the impeller, statical. counter-pressure et [luid in theclearance-simce 'for resisting back-flow without producing aradialoutward ttow through said space oit the tluid discharging t'i'ointhepump.

2.1'11 a` centrifugal pump, an iinpeller provided with ineaA s torpreventing backlealiage oit Afluid through the clearance-space in thepiunp, said'nieans con'iprising annular sliroud-torming walls onopposite sides ot the iinpeller-blades, having on their outer lfacesspiral runways constructed and `arranged to produce and ii'iaintain, by`the i'otation oit the in'ipeller, statical counter-pressure of tluid inthe clearance-space toi' resistingback-How without` producing a radialoutward flow through said space ot the l'luid discharging from the pump.

3. ln a centrifugal pump, the combination with the casing, ot. aniinpeller journaled therein, provided with means 'for preventingback-lealuige ol tluid through the clearance-space in the pump, saidmeans comii'ising annular shroud-torniing walls on opposite sides ot'the iinpeller-blades ei:-

tendingl inwardly from the outer blade-extremities and having on theirouter faces spiral run-ways extending from the inner edges ot said wallsoutwardly and in the direction opposite the direction ot rotation ot'the iinpeller to produce and maintain, by the rotation of the impeller,statical counterpressure o'l [luid in the clearance-space toi' resistingback-flow wit-hout producing a radial outward tlow through said space otthe fluid discharging troni the pump.

JOSEPH, SCHNEBLE.

ln presence oli# .loi-1N W son, Raisin-i' A. Sci-muren.

Copies of this patent may 'ne obtained forifive cents each, byaddressing Ythe Commissioner of Batents,

Washington, D. C.

